KEY BISCAYNE, Florida (AP):

Weary winner Venus Williams stood near the net swatting souvenir balls to cheering fans, but a marathon match had taken its toll, and one attempt didn't even reach the stands.

Williams had already expended all of her energy, erasing a match point and outlasting Aleksandra Wozniak 4-6, 6-4, 7-6 (5) in yesterday's third round at the Sony Ericsson Open.

Williams is playing in her first tournament since withdrawing from the US Open last August after being diagnosed with a fatigue-causing autoimmune disease.

The three-set victory was her second in less than 48 hours and took nearly three hours.

"I just kept coming back," Williams said. "I tried not to let anything discourage me."

"I didn't feel that great and I was kind of starting to panic," Venus said. "I needed to calm down and try to figure out a strategy that was going to work a little better than what I was doing at the moment."